1. Field of the Invention
The present invention relates to a photosensitive resin composition that uses, as an alkali-soluble binder resin, a blend of two kinds of binder resins to ensure the formation of a rectilinear pattern and good adhesion to a substrate while achieving high resolution suitable for use in a transflective liquid crystal display (LCD).
2. Description of the Related Art
A liquid crystal display (LCD) includes upper and lower transparent insulating substrates and a liquid crystal layer interposed therebetween. The liquid crystal layer is formed by injecting a liquid crystal having an anisotropic dielectric constant between the two substrates. Voltages are applied to the liquid crystal layer to change the arrangement of the liquid crystal molecules. This molecular arrangement controls the amount of light passing through the liquid crystal layer to display desired images.
LCDs are not self-luminous devices, and therefore require external light sources. LCDs are broadly classified into transmissive LCDs and reflective LCDs by the type of external light sources they employ.
A transmissive LCD uses a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) as a light source. A reflective LCD reflects external incident light and uses the reflected light as a light source. The transmissive LCD can emit bright light, but it suffers from the drawback of high power consumption. The reflective LCD has the advantage of low power consumption, but it cannot be used when external light is weak.
Various attempts have been made to overcome the limitations of the two types of LCDs. For example, considerable research has been conducted to develop and commercialize transflective LCDs that are driven by a reflective LCD in the presence of an external light source and are driven in a transmissive mode when external light is not sufficient.
A photosensitive resin composition for use in a transflective LCD is required to meet processing characteristics for forming more complex and finer patterns than patterns of existing structures. Another requirement of the photosensitive resin composition is good adhesion to an underlying substrate while forming narrow patterns. In contrast, conventional photosensitive resin compositions cannot simultaneously meet the requirements for the adhesion to underlying substrates and the formation of high resolution fine patterns. That is, some conventional photosensitive resin compositions sacrifice adhesion to underlying substrates to form high resolution fine patterns. Some conventional photosensitive resin compositions with good adhesiveness have difficulty in forming high resolution patterns.